Immersion sampler with a soluble deoxidant

ABSTRACT

A sampler for obtaining a sample of metal from a molten metal bath such as steel includes a soluble deoxidant such as zirconium or titanium located in the inlet passage or sample cavity for killing the molten metal. The deoxidant has a melting point higher than the melting point of the steel melt and dissolves in the melt at a rate which provides uniform deoxidation of the sample. The sampler also includes a smooth fused quartz inlet tube which is connected to a sample mold in the sample cavity and projects from the sampler body to prevent the formation of a skull around the inlet passage to facilitate removal of the sample. The projecting inlet tube also prevents carbon pickup resulting from combustion of the cardboard sleeve typically employed to carry the sample cartridge.

United States Patent [191 Falk IMMERSION SAMPLER WITH A SOLUBLEDEOXIDANT [76] Inventor: Richard A. Falk, 519 Westminster Dr., Waukesha,Wis. 53186 [22] Filed: May 1, 1972 [21] Appl. No.: 249,296

[ Apr. 23, 1974 Primary Examiner-Richard C. Queisser AssistantExaminer-Daniel M. Yasich Attorney, Agent, or Firm-Henry C. Fuller, Jr.

[ 5 7 ABSTRACT v A sampler for obtaining a sample of metal from a mo]-ten metal bath such as steel includes a soluble deoxidant such aszirconium or titanium located in the inlet passage or sample cavity forkilling the molten metal. The deoxidant has a melting point higher thanthe melting point of the steel melt and dissolves in the melt at a ratewhich provides uniform deoxidation of the sample. The sampler alsoincludes a smooth fused quartz inlet tube which is connected to a samplemold in the sample cavity and projects from the sampler body to preventthe formation of a skull around the inlet passage to facilitate removalof the sample. The projecting inlet tube also prevents carbon pickupresultingfrom combustion of the cardboard sleeve typically employed tocarry the sample cartridge.

6 Claims, 6 Drawing Figures BACKGROUND OF INVENTION Molten metalsamplers of the type disclosed in my US. Pat. No. 3,481,201 aretypically provided with a coil or strip of aluminum to kill or deoxidizethe molten steel as it enters the sample cavity of the sampler. Thealuminum readilycombines with the oxygen in the steel and thus minimizesthe free oxygen in the sample which can result in a non-homogeneous orpitted sample which interferes with spectographic analysis of thesample. The aluminum has a melting point less than that of molten steeland thus the aluminum quickly melts upon contact with the molten metaland is washed from the inlet passage by the initial flow of melt. Thealuminum does not remain in the desired location to deoxidize additionalmetal as the sample cavity is filled. This results in non-uniformdeoxidation of the sample. Difficulty is also encountered in removingthe sample from some sample lances because the metal skull formationwhich forms around the exterior of the sampler is connected to the metalin the inlet passage and thus the sample when the lance is cooled.

SUMMARY OF INVENTION The present invention provides an immersion samplerwith a soluble deoxidant for killing the sample which has a highermelting point than the molten metal bath and which dissolves in themolten metal at a rate which insures presence of the deoxidant in theinlet passage during filling of the sample cavity to afford more uniformkilling or deoxidation of the sample and thus improved spectographictest results. Zirconium and titanium have been successfully used assoluble deoxidants.

The invention also provides a sampler which has a smooth fused quartzinlet tube connected to a sample mold for conveying molten metal fromthe bath to the mold and in which the inlet tube projects beyond thebottom wall of the sampler. The molten metal does not adhere to the tubebecause the tube surface is smooth and the portion of the tube exposedto the bath quickly reaches bath temperature. The skull which formsaround the sample does not enclose the end of the tube and thus is notconnected to the sample. The projecting tube also prevents carbon pickupfrom the bath resulting from combustion of the cardboard sleeve carryingthe sample cartridge.

Further objects, advantages and features of the invention will becomeapparent from the following disclosure.

DRAWINGS the sampling FIG. 6 is a view on reduced scale of a sampleobtained with the sampler shown in FIG. 5.

BRIEF DESCRIPTION OF DRAWINGS Although the disclosure hereof is detailedand exact to enable those skilled in the art to practice the invention.the physical embodiments herein disclosed merely exemplify the inventionwhich may be embodied in other specific structure. The scope of theinvention is defined in the claims appended hereto.

In the drawings, FIG. 1 shows a sampling lance 10 having a tubular wall12 which can be steel. The lance 10 has a hollow interior 14 whichcontains a pair of allochiral sample mold sections 16 and 18. The samplemold sections 16, 18 are clamped around a fused quartz inlet tube 20 bya paper tube or sleeve 21. The tube 20 provides an inlet passage to theinternal sample cavity 22 defined by the mold sections 16 and 18. Thesample thus formed provides a pin portion 19 (FIG. 4) suitable forcarbon, sulphur, or wet analysis in an induction combustion analyzer asshown in my US. Pat. No. 3,392,970 and a disc portion 25 of anappropriate size for spectographic analysis.

The inlet tube 20 extends through and is supported by a refractory disc23 which is cemented in the tubular wall by refractory cement. The disc23 is recessed inwardly from the end of the tube so that a bead or ring24 of refractory cement can be placed between the end of the tube andthe disc 23 to retain the disc 23 in position. A fusible cap 30 can alsobe provided for enclosing the open end of the sample passage to preventslag from entering the inlet passage as the lance 10 is lowered into themelt.

Sampling lances having a steel casing such as those shown in FIGS. 1, 3,4 receive a skull formation 42 (FIGS. 3, 4) upon immersion andwithdrawal from the bath.

FIG. 3 shows a prior art sampler in which the end 34 of the tubeproviding the inlet passage is coterminous with the surface 36 of thesampler. The skull 38 that is formed around the end of the sampler uponwithdrawal of theilance from the molten metal bath-is connected to thepin portion of the sample 40 and, interferes'with quick release'of thesample from the sampling lance when the sample has cooled.

FIG. 4 shows the skull formation 42 with a sampling lance in accordancewith the invention in which the tube 20 projects A inch or more from therefractory disc 23. The exposed end 43 of the tube quickly reaches bathtemperature when the sampler is immersed and the skull formation 42 doesnot adhere to the smooth exposed outer end 43 of the tube and is notconnected to the pin portion of sample 44 in the inlet tube enablingquick release of the sample from the lance. A skull formation does notoccur around the entrance port of the sampling lance shown in FIG. 5because of the combustible paper board tube which is partially consumedduring use. However with the inlet tube 78 projecting a distance of :4inch or more from the adjacent end 71 of the tube 70 carbon pickup inthe sample cavity and inlet tube 78 caused by combustion of thecardboard tube 70 is minimized.

The sampling lance of the invention further includes a soluble deoxidantwith a melting point higher than the bath temperature to deoxidize orkill the molten steel as it enters the sample passage or the samplecavity.

3 The killing or deoxidation-of samples is typically done with immersionsampling'lances to provide a sample with a smooth non-pitted surfacesuitable for spectographic analysis. In FIG. 1 the soluble deoxidant 50is in the form of a strip of metal which spans the sample mold sections16 and 18 and is located between adjacent edges of the sample molds tospace the mold sec- .tions 16 and 18 to provide for escape of air and tovent the sample cavity as the molten steel rushes in the inlet tube 20upon immersion in a bath. The deoxidant 50 can be from the group ofzirconium and titanium, both of which have a melting point higher than atemperature of a typical molten steel bath of about 2800F. and aresoluble in a molten steel bath. The melting point of zirconium is about3 lF. and the melting point of titanium is about 3250F. Other solubledeoxidants having a melting point highenthan bath temperatures can beemployed. A strip or coil of soluble deoxidant 52 can also be located inthe inlet tube. The strip. 52 can also be aluminum- FIG. shows amodified embodiment of the invention. Two individual sample molds 72 and74 are located in the interior 76 of the lance 71. The sample molds 72and 74 are also provided with inlet tubes 78 which are anchored in thelance 70 by a refractory disc 80. The inlet tubes 78 have fused quartzsegments 82 and 84 which are interconnected to provide a. continuousflow passage by a tubular segment 86 formed from zirconium or titanium.The tube segment 86 can also bev aluminum. The tube segments 82desirablyhavean inside diameter less than the inside diameter oftubesegment 84 to prevent loss of the sample when the lance is withdrawnfrom the molten metal bath and to prevent rapid filling of the samplecavities which can cause incomplete deo'xidation. An inside diameter oftube section of 7mm and an inside diameter of tube section 82 ofmmicanbe employed. The inside diarneter of the deoit'idant tube section 86 canbe larger than the inside diameter of the tube segment .82 and the samediameter as the tube section 84.

. The sample cavities as of the molds-72, 74 can also be provided with adeoxidant 90 which can be a soluble deoxidant with a melting pointhigher-than bath temperature or analuminum coil.

- The use of a soluble deoxidant inthe inlet tube or .sample cavityinsures the presence of deoxidant during filling of the sample cavity.This deoxidant dissolves in the melt as the. melt enters the sample moldat a rate suchthat the deoxidant remains present in the inlet tube untilthe molds 72 and 74 and inlet tubes 78 are filled thus providing uniformdeoxidation of the sample. Aluminum in the inlet tube quickly melts uponcontact with the molten metal and is washed away from its position inthe tube and thus may not provide complete deoxidation of the sample.

Various combinations of aluminum and soluble deoxidants can be employedin different locations in the sample cavity and inlet tube for optimumresults under differing conditions.

FIG. 5 also shows a modified arrangement for securing the sample moldsections 102,104 in spaced assem bly. A strip or spacer of metal 105 islocated between the adjacent edges of the mold sections 102, 104 andwelded at 101 to both mold sections. The strip 105 can be provided witha projecting tab 108 useable to affix data or information tosubsequently identify the sample when taken from the mold. Theinformation can be stamped on the tab 108 prior to use of the sampler. Atab portion 110 extends into the mold cavity and thusthe tab portion 108is molded into and anchored in the sample 1 12 as shown in FIG. 6. Thusthe samples can subsequently be identified.

What is claimed is:

l. A sampler for obtaining a sample of molten metal comprising wallmeans defining an interior sample cavity, walls defining a sample entrypassage communicating with said cavityfor receiving a sample of moltenmetal, and wherein said wall means defining said sample cavity comprisesan entrance passage and two opposed mold parts and including a soluble.deoxidant havinga melting point higher than the melting point of themolten metal in the form of a strip of metal located between adjacentedges of said two opposed mold parts of the wall means defining saidsample cavity remote from said entrance passage and spanning said samplecavity and separating said mold parts to provide a gap between saidadjacent edges for venting air from said mold as the sample enters andfills said mold and said sample cavity serving as a mixing chamber formixing said deoxidant with said sample. I

2. A sampler in accordance with claim 1 wherein'said deoxidant is fromthe group of zirconium, titanium.

-3. A sampler for obtaining at least one sample of molten metalcomprising walls defining an interior sample cavity, walls defining asample inlet passage communicating with said cavity and for receiving asample of molten metal, and wherein said walls defining said inletpassage comprise two tubular fused quartz segments and a solubledeoxidant in the form of a tubular segment located intermediate of andintegrally connecting said quartz segments and arefractory disc havingan aperture located in the end of the sampler for supporting said wallsdefining said sample inlet passage with said tubular deoxidant segmentlocated wholly within said aperture and said quartz segments havingportions located within said aperture and portions projecting outwardlytherefrom with one of said quartz segments having a free end toprovide'a nonskull adhering surface, said deoxidant tubular segmenthaving an inner diameter greater than the inner diameter of the quartzsegments to prevent loss of the sample as it is withdrawn from themolten metal. 7

4. A sampler in accordance with claim 3 in which said sampler has an endwall and wherein one of said quartz segments projects outwardly fromsaid end wall at least l4 of an inch.

5. A sampler in accordance with claim 3 wherein said quartz segmentprojecting outwardly of said end wall has an inside diameter less thanthe other of said quartz segments to minimize outflow of said sample.

6. A sampler for obtaining a sample of molten metal comprising a samplecartridge having an internal sample cavity and an end wall, an inletpassage extending through said end wall and communicating with saidsample cavity, said inlet passage comprising integrally connectedsegments formed of at least one fused quartz tubular segment and atubular segment of a metallic deoxidant having a melting point higherthan the temperature of the molten metal, said metallic deoxidanttubular segment being soluble in said molten metal and combinable withoxygen in said molten metal when dissolved in said molten metal, saiddeoxidant segment providing a portion of the flow path of said moltenmetal from the molten metal source through said inlet 6 less than theinside diameter of said metallic deoxidant segment to retard outflow ofmetal from said passage upon removal of said sampler from a bath ofmolten metal.

1. A sampler for obtaining a sample of molten metal comprising wallmeans defining an interior sample cavity, walls defining a sample entrypassage communicating with said cavity for receiving a sample of moltenmetal, and wherein said wall means defining said sample cavity comprisesan entrance passage and two opposed mold parts and including a solubledeoxidant having a melting point higher than the melting point of themolten metal in the form of a strip of metal located between adjacentedges of said two opposed mold parts of the wall means defining saidsample cavity remote from said entrance passage and spanning said samplecavity and separating said mold parts to provide a gap between saidadjacent edges for venting air from said mold as the sample enters andfills said mold and said sample cavity serving as a mixing chamber formixing said deoxidant with said sample.
 2. A sampler in accordance withclaim 1 wherein said deoxidant is from the group of zirconium, titanium.3. A sampler for obtaining at least one sample of molten metalcomprising walls defining an interior sample cavity, walls defining asample inlet passage communicating with said cavity and for receiving asample of molten metal, and wherein said walls defining said inletpassage comprise two tubular fused quartz segments and a solubledeoxidant in the form of a tubular segment located intermediate of andintegrally connecting said quartz segments and a refractory disc havingan aperture located in the end of the sampler for supporting said wallsdefining said sample inlet passage with said tubular deoxidant segmentlocated wholly within said aperture and said quartz segments havingportions located within said aperture and portions projecting outwardlytherefrom with one of said quartz segments having a free end to providea non-skull adhering surface, said deoxidant tubular segment having aninner diameter greater than the inner diameter of the quartz segments toprevent loss of the sample as it is withdrawn from the molten metal. 4.A sampler in accordance with claim 3 in which said sampler has an endwall and wherein one of said quartz segments projects outwardly fromsaid end wall at least 1/4 of an inch.
 5. A sampler in accordance withclaim 3 wherein said quartz segment projecting outwardly of said endwall has an inside diameter less than the other of said quartz segmentsto minimize outflow of said sample.
 6. A sampler for obtaining a sampleof molten metal comprising a sample cartridge having an internal samplecavity and an end wall, an inlet passage extending through said end walland communicating with said sample cavity, said inlet passage comprisingintegrally connected segments formed of at least one fused quartztubular segment and a tubular segment of a metallic deoxidant having amelting point higher than the temperature of the molten metal, saidmetallic deoxidant tubular segment being soluble in said molten metaland combinable with oxygen in said molten metal when dissolved in saidmolten metal, said deoxidant segment providing a portion of the flowpath of said molten metal from the molten metal source through saidinlet passage into said sample cavity and being soluble in the moltenmetal at a rate such that deoxidant remains present in the inlet tubeuntil the sample cavity fills with metal to provide uniform deoxidationof the sample and wherein said fused quartz segment projects outwardlyfrom said end wall and has an inside diameter less than the insidediameter of said metallic deoxidant segment to retard outflow of metalfrom said passage upon removal of said sampler from a bath of moltenmetal.